Presenting the findings at the 2017 San Antonio Breast Cancer Symposium in Texas, USA, author Matteo Lambertini (Institut Jules Bordet and Université Libre de Bruxelles, Belgium) explained that GnRHa-induced ovarian suppression “is considered experimental by the ASCO and ESMO guidelines on fertility preservation in cancer patients” and that its role remains “highly controversial.”

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He continued, however, that the current study “provides level 1A of evidence for the efficacy and safety of temporary ovarian suppression with [a] GnRHa during chemotherapy in premenopausal early breast cancer patients.”

Lambertini and colleagues pooled individual patient data from five trials, of which the PROMISE-GIM6 and Moffitt-led studies investigated the addition of triptorelin, while the POEMS/SWOG S0230, GBG-37 ZORO, and Anglo Celtic Group OPTION trials assessed goserelin.

Premature ovarian insufficiency, as per the definition used in the included trials, occurred in 14.1% of the 436 women who were randomly assigned to receive GnRHa therapy alongside chemotherapy and 30.9% of 437 participants who received just chemotherapy. This equated to a significant odds ratio (OR) of 0.38 after adjusting for age, estrogen receptor status, and the type and duration of chemotherapy.

The groups were comparable with respect to amenorrhea rates at 1 year after the completion of chemotherapy, with rates of 36.8% and 40.4% in the GnRHa and control groups, respectively. But by the 2-year mark, the amenorrhea rate was significantly lower in the GnRHa treatment arm, at 18.2% versus 30.0% for the control arm and an adjusted OR of 0.51.

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Thirty-seven GnRHa-treated women became pregnant after the end of chemotherapy as did 20 women in the control group, giving a significant incidence rate ratio of 1.83 in favor of ovarian suppression. Lambertini said in a press release that despite the low absolute numbers, this finding “suggests that GnRHa during chemotherapy is not only a strategy to preserve ovarian function but may also potentially improve future fertility.”

Furthermore, disease-free and overall survival did not differ significantly between women who did and did not receive GnRHa.

In light of these results temporary ovarian suppression “should be considered as an option to reduce the likelihood of chemotherapy-induced [premature ovarian insufficiency] and potentially improve future fertility in premenopausal early breast cancer patients undergoing (neo)adjuvant chemotherapy,” concluded Lambertini.